stash/rebase: default to the non-builtin versions

The upcoming Git for Windows v2.19.0 wants to ship with the builtin
versions of stash, rebase and rebase -i. The reason: these are just *so
much faster*: t3400 and t3404 run about 60-70 percent faster, and t3903
even more than 80% faster.

However, these are still all pretty fresh, still being reviewed and
iterated on the Git mailing list.

So let's try to give users a way to test these (or to boldly use them
for their mission-critical tasks, as this here developer plans on
doing), but stay with the safe option by default: use the scripted
versions (which might be slow, but they are well tested).

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

builtin/rebase.c

@@ -54,7 +54,7 @@ static int use_builtin_rebase(void)
 	cp.git_cmd = 1;
 	if (capture_command(&cp, &out, 6)) {
 		strbuf_release(&out);
-		return 1;
+		return 0;
 	}
 
 	strbuf_trim(&out);

builtin/stash.c

@@ -1488,7 +1488,7 @@ static int use_builtin_stash(void)
 	cp.git_cmd = 1;
 	if (capture_command(&cp, &out, 6)) {
 		strbuf_release(&out);
-		return 1;
+		return 0;
 	}
 
 	strbuf_trim(&out);